High pitched “whistle” on channel 1 “pushed” with any gain?

Discussion area for Single, Dual and Trip Rectifers

Moderators: Guitarzan, Grandor, ned, Platypus

Post Reply
Exodus5
Bottle Rocket
Posts: 9
Joined: Sat Feb 01, 2014 6:46 pm

High pitched “whistle” on channel 1 “pushed” with any gain?

Post by Exodus5 » Thu Jul 12, 2018 8:25 pm

I just bought a mid-2000’s Dual Rectifier (3-channel) and it sounded OK when I tried it out but after the long car ride home When I turned it on at home I found that any time I hit a chord (or note) on channel 1 while in pushed The output changed to a hug pitched whistle/squeal. I checked my connections, etc, but finally realized that the squeal “followed” the channel 1 gain control. When I’m playing clean there is no squeal, but is soon as I push it over to pushed I find any amount of gain above about two brings about the loud squeal. If I start out with no gain and start playing and slowly turn up again at about 1/4 the output turns into a squeal and that squeal only changes in pitch the more I turn up the gain. What the heck is happening here?

Exodus5
Bottle Rocket
Posts: 9
Joined: Sat Feb 01, 2014 6:46 pm

Re: High pitched “whistle” on channel 1 “pushed” with any ga

Post by Exodus5 » Fri Jul 13, 2018 7:35 am

Update: Nevermind. Apparently V1 was junk. Replaced it and we are back to normal.

User avatar
deeman
Mark III
Posts: 261
Joined: Mon Jan 14, 2013 4:13 pm
Location: Chicago, IL
Contact:

Re: High pitched “whistle” on channel 1 “pushed” with any ga

Post by deeman » Fri Jul 13, 2018 9:48 am

Hey, glad you were able to resolve the issue!
Mesa Boogie 2001 3 Channel Dual Rectifier
Ampeg 4x12 Cab
Gibson 2006 Les Paul Studio
https://soundcloud.com/authoritydrive

woodbutcher65
Mark III
Posts: 152
Joined: Fri May 04, 2018 10:36 pm

Re: High pitched “whistle” on channel 1 “pushed” with any ga

Post by woodbutcher65 » Wed Jul 18, 2018 3:20 pm

That particular quirk of channel 1 in the pushed mode actually makes it very handy for testing preamp tubes. I use it for exactly that purpose.

In general, any tube that whistles in channel 1 pushed, before gain is at 10, is probably an old, well used tube that will not provide satisfactory performance in any high gain application. I might set aside a few for use as phase inverters or reverb circuit tubes. They're going to be junk if used in a high gain stage.

Post Reply